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/*
* Copyright 2014 The Netty Project
*
* The Netty Project licenses this file to you under the Apache License,
* version 2.0 (the "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
package org.glowroot.shaded.netty.util.internal;
import sun.misc.Unsafe;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.concurrent.atomic.AtomicIntegerFieldUpdater;
final class UnsafeAtomicIntegerFieldUpdater extends AtomicIntegerFieldUpdater {
private final long offset;
private final Unsafe unsafe;
UnsafeAtomicIntegerFieldUpdater(Unsafe unsafe, Class tClass, String fieldName) throws NoSuchFieldException {
Field field = tClass.getDeclaredField(fieldName);
if (!Modifier.isVolatile(field.getModifiers())) {
throw new IllegalArgumentException("Must be volatile");
}
this.unsafe = unsafe;
offset = unsafe.objectFieldOffset(field);
}
@Override
public boolean compareAndSet(T obj, int expect, int update) {
return unsafe.compareAndSwapInt(obj, offset, expect, update);
}
@Override
public boolean weakCompareAndSet(T obj, int expect, int update) {
return unsafe.compareAndSwapInt(obj, offset, expect, update);
}
@Override
public void set(T obj, int newValue) {
unsafe.putIntVolatile(obj, offset, newValue);
}
@Override
public void lazySet(T obj, int newValue) {
unsafe.putOrderedInt(obj, offset, newValue);
}
@Override
public int get(T obj) {
return unsafe.getIntVolatile(obj, offset);
}
}